What to avoid ?
Avoid overemphasis on pure arithmetic – Pure Arithmetic primarily focuses on computation. Questions seeking direct answers for addition, subtraction , multiplication or division do not require any logical thinking and do nothing to develop logical reasoning.
Avoid Abacus, Vedic maths and other such tools – Abacus and Vedic Maths focus on swift computational techniques which are largely useless from a mathematical standpoint as Maths is mostly about pure, logical reasoning. Chess might be a much better option as it forces the player to reason systematically.